professor, civil eng. dep., shoubra faculty of eng., benha ... shoubra/civil... · influence of...
TRANSCRIPT
Vol 67, No.5;May 2017
Jokull Journal Joku/1 Journal
103
INFLUENCE OF RICE, WHEAT STRAW ASH & RICE HUSK ASH ON THE
PROPERTIES OF CONCRETE MIXES
T. A. EL-SAYED1*, A. M. ERFAN2, R. M. ABD EL-NABY3 1,2Assistant Professor, Civil Eng. Dep., Shoubra Faculty of Eng., Benha University, Egypt
Professor, Civil Eng. Dep., Shoubra Faculty of Eng., Benha University, Egypt
ABSTRACT
Three different types of husks were used, Wheat Straw, Rice Straw, and Rice Husk. The
X-ray diffraction and the chemical analysis were carried out on the three wheat and rice
husk ashes. The purposes were to verify the pozolanic reactivity and the existence of any
harmful ingredients. The percentage of the husk ashes were 5%, 10%, 15%, and 20% of
the weight of the cement. The workability was measured by the slump test. The densities
of the different mixes were computed. The pulse velocity and the sorptivity were also
computed. The compressive and tensile strengths were also estimated.
KEYWORDS
Wheat Straw Ash (WSA), Rice Straw Ash (RSA), Rice Husk Ash (RHA), X-ray
diffraction, chemical analysis, slump test, sorptivity.
1. PROBLEM DIFINISTION Rice straw and husk were an agricultural residue from rice cultivation and milling Process.
The annual world rice production for 2007 was estimated by 649.7 million tons, the husk
constitute approximately 20 % of It. Rice wastes are residue production in significant
quantities on a global basis. While they are utilized in some regions; in others are wastes
causing pollution and problems with disposal. When rice straw and rice husk burnt, the
ash is highly pozzolanic and Suitable for use in lime-pozzolana mixes and Portland
cement replacement.
* Corresponding author. Taha Awad Allah El-Sayed Ibrahim Tel.: +20 1008444985, Fax: +202 22911118, Official Website: http://www.bu.edu.eg/staff/tahaibrahim3 Email address: [email protected] (T. A. EL-Sayed)
104 Jokull Journal
Vol 67, No.5;May 2017
During growth, rice and wheat plants absorb silica from the soil and accumulate it into
their structures. It is this silica, concentrated by burning at high temperatures removing
other elements, which make the ash so valuable. Amongst the agricultural waste, rice
straw, rice husk and wheat straw have a very high potential for the production of very
effective secondary raw material. It is mainly due to its random availability, very high
silica content and relatively low cost. RHA contains around 85% - 90% amorphous silica
which obtains from the soil combines with calcium hydroxide to increase the strength. It is
known that cement production is accompanied by the emission of huge amounts of CO2, a
greenhouse gas, into the atmosphere. It represent 7% of carbon dioxide has produced in
the world, so that using rice straw and husk is more beneficial to the environment, the cost
of producing Portland cement is very high, so that using rice straw and husk in concrete
mixes is more economically.
2. INTRODUCTION
To enhance the durability of concrete, numerous added substances are utilized. These
added substances likewise diminish the cost of cement [1–6]. Rice and wheat straw ash is
utilized as a pozzolanic added substance [7]. Rice and wheat straw ash remains can be
additionally used as a solid added substance because of its high silicium content [8]. For
the change of the properties of cement mortar and cement concrete or the development
cost to be monetary, admixtures are included with the concrete blend and these are either
normally happening mixes or chemicals delivered in mechanical process. The majority of
the admixtures are pozzolans. Pozzolan is a powdered material, which when added to the
cement in the mix reacts with lime, discharged by the hydration of the cement, to make
mixes which enhance the quality or different properties of the concrete or mortar [9]. As
per ASTM [10] after chemical analysis if the sum of Iron oxide (Fe2O3), Silicon oxide
(SiO2) and Aluminum oxide (Al2O3) is over 70% then the material would be pronounced
as a pozzolanic material. It is observed by many researchers that there is an increase of
compressive strength of mortar with the use of pozzolanic materials. The increase in
compressive strength could be attributed to the reduced water content, the filler effect, and
the higher pozzolanic reaction. The fine fineness of pozzolans had a greater pozzolanic
reaction and the small particles could also fill in the voids of the mortar mixture, thus
increasing the compressive strength of the mortar [11]. The use of supplementary
105 Jokull Journal
Vol 67, No.5;May 2017
cementitious materials, such as fly ash, silica fume, and blast furnace slag, in concrete
construction is widespread. Supplementary cementitious materials may considerably
improve the strength and durability of concrete [12], [13].
Different specialists who concentrate on the conceivable utilizations of burned slag have
examined building and development materials. Other than tackling transfer issues,
monetary, biological, and vitality sparing is another favorable position of burned fiery
debris reuse in the development business. As per other reviews [14–16], cremation by-
items that could conceivably be utilized as pozzolanic materials in the development
business includes paper sludge ash, rice husk ash (RHA), and sewage sludge ash. The
utilization of these burned slags as halfway substitutions for bond presents the ecological
advantages of waste reuse and CO2 investment funds by diminishing the cement content
and change of material mechanical properties. Among these by- products, RHA has pulled
in intrigue in view of its high undefined silica content. Several reviews have utilized RHA
as a low-cost and superior building material [17, 18]. In spite of the fact that co-
combustion of rice husk and sewage sludge gives promising application prospects, just
few reviews have been led.
3. RESEARCH SIGNIFICANCE “OBJECTIVES” 1- Studying the effect of using three different ashes as cement replacement or filling
materials on the physical and mechanical properties of the concrete mixes.
2- Studying the effect of the percentage of the ashes on the physical and mechanical
properties of the concrete mixes.
4. EXPERIMENTAL PROGRAM
4.1 Concrete Mixes
All concrete mixes were designed by absolute volume method according to ACI 211. The
mix proportions of the concrete mixes - in kg/m3 are given in Table (1). All the concrete
mixes made with 0.5 w/c ratio. M0 is the corresponding control Normal weight concrete.
Chart 1&2 illustrates the scheme of the experimental program.
106 Jokull Journal
Vol 67, No.5;May 2017
Table 1: Mix design
Mix type W/C Rice straw
powder
Rice husk
powder
Wheat straw
powder
Cement (kg)
Water (kg)
Sand (kg)
C. Agg. (kg)
M0 0.5 - - - 400 200 725 1075 WSA5% 0.5 5% - - 380 200 725 1075 WSA10% 0.5 10% - - 360 200 725 1075 WSA15% 0.5 15% - - 340 200 725 1075 WSA20% 0.5 20% - - 320 200 725 1075 RSA5% 0.5 - 5% - 380 200 725 1075
RSA10% 0.5 - 10% - 360 200 725 1075 RSA15% 0.5 - 15% - 340 200 725 1075 RSA20% 0.5 - 20% - 320 200 725 1075 RHA5% 0.5 - - 5% 380 200 725 1075 RHA10% 0.5 - - 10% 360 200 725 1075 RHA15% 0.5 - - 15% 340 200 725 1075 RHA20% 0.5 - - 20% 320 200 725 1075
Chart 1: The experimental program Chart 2: The tested variables
107 Jokull Journal
Vol 67, No.5;May 2017
4.2 Testing procedures of Fresh concrete
The slump test was conducted after 20, 40, 60 minutes after mixing to measure the slump
loss of the concrete mixes. Figure 1, shows slump test.
Figure 1: Slump test
4.3 Testing procedures of hardened concrete
4.3.1 Compressive strength test
100x100x100 mm cubical specimens were used for determination of compressive strength
for concrete mixes. The reported values of compressive strength of concrete cubes
represent the average results of three specimens. The load setup is shown in Figure 2.
Figure 2: Compression test machine
108 Jokull Journal
Vol 67, No.5;May 2017
4.3.2 Indirect tension strength test
The splitting tensile strength test was carried out on cylindrical specimens of 100 mm
diameter and 200 mm height as shown in Figure 3. The test was carried out on SSD
condition at an age of 28 days. The reported values of splitting tensile strength of concrete
represent the average results of three specimens. The splitting tensile strength was
calculated using the following equation:
T = 2P/πLD ………………………. Equation (1)
Where; T = Splitting tensile strength (N/mm²), P = Maximum (failure) load (N), L = Length of the specimen (mm), and D = Diameter of the specimen (mm).
Figure 3: Splitting test
4.3.3 Ultrasonic pulse velocity
Longitudinal pulse velocity (m/s) is given by:
V= L /T ………………………. Equation (2)
Where: V is the longitudinal pulse velocity (m/s), L is the path length (m), T is the time taken by the pulse to traverse that length (s).
109 Jokull Journal
Vol 67, No.5;May 2017
4.3.4 Porosity Test
The porosity can be calculated as follow:
Porosity = volume of the voids/volume of the specimen
= Vv/Vo*100 = (W1-W2)*100/Vo ………………………. Equation (3)
Where:
W1= weight of saturated specimen, W2=weight of dry specimen,
4.3.5 Water absorption by capillary action, the sorptivity
The sorptivity test was carried out using a plastic container filled with water to a depth of
20 mm. Steel bars of 18 mm diameter were rested on the bottom of the container such that,
the water was just above the top surface of the steel bars as shown in Figure 4. The
specimens were weighed using digital electric balance of 0.001 and 0.1 gm accuracy for
mortar and concrete specimens respectively.
Sorptivity of the tested specimens was calculated using the following equation. The results
were an average of triplicate measurements taken after 28 and 56 days.
i = St1/2 ………………………. Equation (4)
Where,
i = increase in mass (g/mm2). t = time, measured (min), at which the weight is determined, S = sorptivity (mm/min1/2).
Figure 4: Sorptivity test
110 Jokull Journal
Vol 67, No.5;May 2017
5. RESULTS AND ANALYSIS 5.1 X ray diffraction
X-ray diffraction analysis was carried out on three samples of ashes RHA, RSA and WSA.
The results of the three ashes are shown in Figures 5, 6 and 7.
Figure 5: XRD patterns of gray rice husk ash
Figure 6: XRD patterns of gray rice straw ash
Figure 7: XRD patterns of gray wheat straw ash
5.2 Chemical analysis
Table 2 showed the potential of pozolanic reaction. The results showed that samples of the
ashes of rice straw has interacted with 14% of quicklime and the ashes of wheat straw
with 16%.
111 Jokull Journal
Vol 67, No.5;May 2017
Table 2: Potential of pozolanic reaction
Interaction duration Quicklime % which interacted with ashes
Cao Gray rice straw ash
RSA (016/160)
Black rice husk ash RHA
(016/161)
Gray wheat straw ash WSA
(016/162)
After 30 min. 35 ml
14.2 14 16
After 5 days at 60oc 14.2 14 16
5.3 Slump test results
Table 3 shows that slump test results for fresh concrete mixes of (Mo, WSA, RSA and
RHA). Table 3: Slump test results
Sample ID Percentage
of ash Slump (mm)
CONTROL 0% 6.5
WSA
5% 5
10% 4
15% 5.5
20% 4.5
RHA
5% 3.5
10% 3.5
15% 6.5
20% 4.5
RSA
5% 4
10% 5.5
15% 6.5
20% 5
112 Jokull Journal
Vol 67, No.5;May 2017
5.4 Density test results
Figure 8 shows the effect of % of ash on the density of concrete mixes. Figures showed
that increasing % of ash from 5% to 15% leads to the increase of the density from 2342 to
2466 Kg/m2, while increasing the % of ash from 15% to 20% lead the decreasing the
density to 2400 Kg/m2. The highest value of density was observed at 15% WSA as a
replacement material.
Figure 8: Influence of % of ash on density after 7 days of curing
5.5 Hardened concrete 5.5.1 Compressive strength results
Figures 9&10 show the effect of type of ash on compressive strength at 7 & 28 days
respectively of concrete mixes. Figure 9 showed that increasing % of ash from 5% to 15%
leads to the increase of the compressive strength from 19.80 to 25.61 N/mm2, while the
increasing the % of ash from 15% to 20% lead the decreasing the compressive strength to
23.41 N/mm2. The highest compressive strength was observed at 15% WSA as a
replacement material. Figure 10 showed that increasing % of ash from 5% to 15% leads to
the increase of the compressive strength from 37.25 to 45.90 N/mm2, while the increasing
the % of ash from 15% to 20% lead the decreasing the compressive strength to 40.65
N/mm2. The highest compressive strength was observed at 15% WSA as a replacement
material.
113 Jokull Journal
Vol 67, No.5;May 2017
Figure 9: Influence of % of ash on compressive strength after 7 days of concrete mixes
Figure 10: Influence of % of ash on compressive strength after 28 days of concrete mixes
5.2.2 Tensile strength results
Figures 11 & 12 show the effect of type of ash on tensile strength after 7& 28 days
respectively of concrete mixes. Figure 11 showed that increasing % of ash from 5% to
15% leads to the increase of the tensile strength from 1.94 to 2.19 N/mm2. While
increasing the % of ash from 15% to 20% leading to decrease the tensile strength to 1.29
N/mm2. The highest tensile strength was observed at 15% WSA as a replacement material.
Figure 10 showed that increasing % of ash from 5% to 15% leads to the increase of the
tensile strength from 2.26 to 3.11 N/mm2. While increasing the % of ash from 15% to 20%
leading to decrease the tensile strength to 2.95 N/mm2. The highest tensile strength was
observed at 15% WSA as a replacement material.
114 Jokull Journal
Vol 67, No.5;May 2017
Figure 11: Influence of % of ash on tensile strength after 7 days of concrete mixes
Figure 12: Influence of % of ash on tensile strength after 28 days of concrete mixes
5.6 Ultrasonic test results
Figure 13 shows the effect of type of ash on the pulse velocity of concrete mixes. Figure
13 showed that changing type of ash leads to the increase of the pulse velocity from 3703
to 3846 m/s. The highest value of pulse velocity was observed at 15% WSA as a
replacement material.
115 Jokull Journal
Vol 67, No.5;May 2017
Figure 13: Influence of % of ash on pulse velocity of concrete
5.7 Sorpitivty test results
Figures 14, 15 &16 show the effect of % of ashes on the sorpitivity of concrete mixes.
Figures showed that increasing % of ash from 5% to 15% leads to decreasing sorpitivty
from 0.5 to 0.354 m.s-0.5, while increasing % of ash from 15% to 20% leads to the
increasing of sorptivity from 0.354 to 0.65 m.s-0.5. The highest value of sorpitivity was
observed at 15% WSA as a replacement material.
Figure 14: Influence of % of RSA on sorpitivity of concrete
116 Jokull Journal
Vol 67, No.5;May 2017
Figure 15: Influence of % of WSA on sorpitivity of concrete
Figure 16: Influence of % of RHA on sorpitivity of concrete
117 Jokull Journal
Vol 67, No.5;May 2017
6. CONCLUSION The main conclusions can be summarized as follows:
1. Using the Wheat and Rice straw Ash and Rice Husk Ash improved the
compressive and tensile strength of the concrete specimens.
2. The Wheat Straw Ash showed the highest value of the compressive and tensile
strength with respect to the Rice Straw and Rice Husk ash.
3. Adding the ash with 15% of the weight of the cement showed the highest
compressive and tensile strength with respect to the 5%, 10%, and 20%.
4. The maximum values of the compressive and tensile strength were shown foe the
case of using 15% wheat Straw Ash.
5. The durability of the concrete was significantly improved for the case of using the
ash with 15% of the cement and the best result for the durability in terms of
density, sorptivity, and strength was obtained for the case of 15% Wheat Straw
Ash.
7. Recommendations for future work:
1. The technique of burning the straw and husk should be carried out using well
prepared furnace to insure temperature stabilization and complete burning of the
straw and husk.
2. Grinding the ash after burning is very important to insure the required surface area.
8. REFERENCES [1] H. Binici, O. Aksogan, Sulphate resistance of plain and blended cement, Cement
Concr. Compos. 28 (2006) 39–46.
[2] J. Tikkanen, A. Cwirzen, V. Penttala, Effects of mineral powders on hydration process
and hydration products in normal strength concrete, Constr. Build. Mater. 72 (2014) 7–
14.
[3] H. Binici, R. Gemci, O. Aksogan, H. Kaplan, Insulation properties of bricks made
with cotton and textile ash wastes, Int. J. Mater. Res. 101 (2010) 894–899.
118 Jokull Journal
Vol 67, No.5;May 2017
[4] G.C. Isaia, A.L.G. Gastaldini, R. Moraesl, Physical and pozzolanic action of mineral
additions on the mechanical strength of high-performance concrete, Cement Concr.
Compos. 25 (2003) 69–76.
[5] H. Binici, O. Aksogan, A.H. Sevinc, A. Kucukonder, Mechanical and radioactivity
shielding performances of mortars made with colemanite, barite, ground basaltic pumice
and ground blast furnace slag, Constr. Build. Mater. 50 (2014) 177–183.
[6] O. Cakır, Experimental analysis of properties of recycled coarse aggregate (RCA)
concrete with mineral additives, Constr. Build. Mater. 68 (2014) 17–25.
[7] H. Biricik, F. Akoz, I. Berktay, A.N. Tulgar, Study of pozzolanic properties of wheat
straw ash, Cem. Concr. Res. 29 (1999) 637–643.
[8] J. Bensted, J. Munn, A discussion of the paper: ‘‘Study of pozzolanic properties of
wheat straw ash” by Biricik H., Akoz F., Berktay I., Tulgar A.N., Cem. Concr. Res. 30
(2000) 1507–1508.
[9] B. King, A Brief Introduction to Pozzolans. in: Alternative Construction -
Contemporary Natural Building Methods, John Wiley & Sons, London, 2000.
[10] Specification for Fly Ash and Raw or Calcium Natural Pozzolona for Use as a
Material Admixture in Portland Cement Concrete, ASTM C 618-78, American Standard
for Testing Materials, 1978.
[11] G. C. Isaia, A. L. G. Gastaldini, and R. Moraes, “Physical and pozzolanic action of
mineral additions on the mechanical strength of high-performance concrete,” Cem.
Concr. Compos., vol. 25, Issue 1, pp. 69-76, 2003.
[12] V. Papadakis, M. Fardis, and C. Vayenas, “Hydration and carbonation of pozzolanic
cements,” ACI Mater, pp.119– 130, 1992.
119 Jokull Journal
Vol 67, No.5;May 2017
[13] B. March, R. Day, and D. Bonner, “Pore structure characteristics affecting the
permeability of cement paste containing fly ash,” Cem. Concr. Res. pp. 1027– 1038,
1985.
[14] R. García, R.V.D.L. Villa, I. Vegas, The pozzolanic properties of paper sludge
waste, Constr. Build. Mater. 22 (7) (2008) 1484–1490.
[15] S.K. Agarwal, Pozzolanic activity of various siliceous materials, Cem. Concr.
Res. 36 (9) (2006) 1735–1739.
[16] S.C. Pan, D.H. Tseng, C.C. Lee, C. Lee, Influence of the fineness of sewage sludge
ash on the mortar properties, Cem. Concr. Res. 33 (11) (2003) 1749–1754.
[17] J.S. Coutinho, The combined benefits of CPF and RHA in improving the durability
of concrete structures, Cement Concr. Compos. 25 (1) (2003) 51–59.
[18] M.H. Zhang, High-performance concrete incorporating rice husk ash as a
supplementary cementing material, ACI Mater. J. 93 (6) (1996) 629–636.